Featured Research

from universities, journals, and other organizations

Astronomers look to neighboring galaxy for star formation insight

Date:
December 2, 2011
Source:
University of Illinois at Urbana-Champaign
Summary:
An international team of astronomers has mapped in detail the star-birthing regions of the nearest star-forming galaxy to our own, a step toward understanding the conditions surrounding star creation. They found a large number of relatively low-mass clouds of molecular hydrogen -- material for star forming -- and found a correlation between young massive stars and molecular clouds.

A color image of the Large Magellanic Cloud galaxy combining maps of neutral atomic hydrogen gas (red), hydrogen ionized by nearby young stars (blue), and new data from Wong’s team which roughly trace dense clouds of molecular hydrogen (green).
Credit: Photo by Tony Wong

An international team of astronomers has mapped in detail the star-birthing regions of the nearest star-forming galaxy to our own, a step toward understanding the conditions surrounding star creation.

Led by University of Illinois astronomy professor Tony Wong, the researchers published their findings in the December issue of the Astrophysical Journal Supplement Series.

The Large Magellanic Cloud (LMC) is a popular galaxy among astronomers both for its nearness to our Milky Way and for the spectacular view it provides, a big-picture vista impossible to capture of our own galaxy.

"If you imagine a galaxy being a disc, the LMC is tilted almost face-on so we can look down on it, which gives us a very clear view of what's going on inside," Wong said.

Although astronomers have a working theory of how individual stars form, they know very little about what triggers the process or the environmental conditions that are optimal for star birth. Wong's team focused on areas called molecular clouds, which are dense patches of gas -- primarily molecular hydrogen -- where stars are born. By studying these molecular clouds and their relationship to new stars in the galaxy, the team hopes to learn more about the metamorphosis of gas clouds into stars.

"When we study star formation, an important question is, what is the environment doing? How does the location of star formation reflect the conditions of that environment? There's no better place to study the wider environment than the LMC."

Using a 22-meter-diameter radio telescope in Australia, the astronomers mapped more than 100 molecular clouds in the LMC and estimated their sizes and masses, identifying regions with ample material for making stars. This seemingly simple task engendered a surprising find.

Conventional wisdom states that most of the molecular gas mass in a galaxy is apportioned to a few large clouds. However, Wong's team found many more low-mass clouds than they expected -- so many, in fact, that a majority of the dense gas may be sprinkled across the galaxy in these small molecular clouds, rather than clumped together in a few large blobs.

"We thought that the big clouds hog most of the mass," Wong said, "but we found that in this galaxy, it appears that the playing field is more level. The low-mass clouds are quite numerous and they actually contribute a significant amount of the mass. This provides the first evidence that the common wisdom about molecular clouds may not apply here."

The large numbers of these relatively low-mass clouds means that star-forming conditions in the LMC may be relatively widespread and easy to achieve. The findings raise some interesting questions about why some galaxies stopped their star formation while others have continued it.

To better understand the connection between molecular clouds and star formation, the team compared their molecular cloud maps to maps of infrared radiation, which reveal where young stars are heating cosmic dust.

For the comparison, they exploited a carefully selected sample of newborn heavy stars compiled by U. of I. astronomy professor You-Hua Chu and resident scientist Robert Gruendl, who also were co-authors of the paper. These stars are so young that they are still deeply embedded in cocoons of gas and dust.

"It turns out that there's actually very nice correspondence between these young massive stars and molecular clouds," Wong said. "That's not entirely surprising, but it's reassuring. We assume that these stars have to form in molecular clouds, and it tells us that the molecular clouds do hang around long enough for us to see them associated with these massive young stars."

Wong hopes to continue to study the relationship between molecular clouds and star formation in greater detail. If researchers can determine the relative ages of young stars, they can correlate these against molecular clouds to figure out which clouds have star formation, how long the clouds live and what eventually leads to their destruction. They also plan to use a newly constructed array of telescopes in Chile to see the cloud environment in higher resolution, pinpointing exactly where inside the molecular cloud star formation will occur.

"This study provides us with our most detailed view of an entire population of clouds in another galaxy," Wong said. "We can say with great confidence that these clouds are where the stars form, but we are still trying to figure out why they have the properties they do."

The National Science Foundation and NASA supported this work.


Story Source:

The above story is based on materials provided by University of Illinois at Urbana-Champaign. Note: Materials may be edited for content and length.


Journal Reference:

  1. Tony Wong, Annie Hughes, Jόrgen Ott, Erik Muller, Jorge L. Pineda, Jean-Philippe Bernard, You-Hua Chu, Yasuo Fukui, Robert A. Gruendl, Christian Henkel, Akiko Kawamura, Ulrich Klein, Leslie W. Looney, Sarah Maddison, Yoji Mizuno, Deborah Paradis, Jonathan Seale. The Magellanic Mopra Assessment (MAGMA). I. The Molecular Cloud Population of the Large Magellanic Cloud. The Astrophysical Journal Supplement Series, 2011; 197 (2): 16 DOI: 10.1088/0067-0049/197/2/16

Cite This Page:

University of Illinois at Urbana-Champaign. "Astronomers look to neighboring galaxy for star formation insight." ScienceDaily. ScienceDaily, 2 December 2011. <www.sciencedaily.com/releases/2011/11/111130141901.htm>.
University of Illinois at Urbana-Champaign. (2011, December 2). Astronomers look to neighboring galaxy for star formation insight. ScienceDaily. Retrieved August 21, 2014 from www.sciencedaily.com/releases/2011/11/111130141901.htm
University of Illinois at Urbana-Champaign. "Astronomers look to neighboring galaxy for star formation insight." ScienceDaily. www.sciencedaily.com/releases/2011/11/111130141901.htm (accessed August 21, 2014).

Share This




More Space & Time News

Thursday, August 21, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Space to Ground: Hello Georges

Space to Ground: Hello Georges

NASA (Aug. 18, 2014) — Europe's ATV-5 delivers new science and the crew tests smart SPHERES. Questions or comments? Use #spacetoground to talk to us. Video provided by NASA
Powered by NewsLook.com
Tiny Satellites, Like The One Tossed From ISS, On The Rise

Tiny Satellites, Like The One Tossed From ISS, On The Rise

Newsy (Aug. 18, 2014) — The Chasqui I, hand-delivered into orbit by a Russian cosmonaut, is one of hundreds of small satellites set to go up in the next few years. Video provided by Newsy
Powered by NewsLook.com
This Week @ NASA, August 15, 2014

This Week @ NASA, August 15, 2014

NASA (Aug. 15, 2014) — Carbon Observatory’s First Data, ATV-5 Delivers Cargo, Cygnus Departs Station and more... Video provided by NASA
Powered by NewsLook.com
Space Shuttle Replica Hoisted for Landmark Exhibit

Space Shuttle Replica Hoisted for Landmark Exhibit

Reuters - US Online Video (Aug. 14, 2014) — The space shuttle replica Independence has been hoisted atop Space Center Houston's shuttle carrier aircraft, creating a monument to the shuttle program which will open to the public next year. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins